1. Field of the Invention
This invention relates to an electrical component such as a rotary switch for use with a variable resistor or the like, and more particularly to a structure for fixing of a sliding element to a holding member.
2. Description of the Related Art
The prior art electrical components as shown in FIGS. 7 to 11, are constructed such that a holding member 21 components, composed of a molded base section made of synthetic resin having a peripheral edge 21a, a flat upper surface 21b, an axial hole 21c arranged at a central part and a plurality of column-like segments 21e. The column-like segments 21e projected upwardly from the flat surface 21b and have a circular bulged-out segment 21d at their upper end part.
In addition, a sliding element 22 formed by a metallic plate is comprised of a flat base segment 22a. A sliding piece 22b is bent relative to the base segment 22a and extends from it. A plurality of holes 22c are arranged in the base segment 22a with a plurality of tongues 22d arranged in the holes 22c.
As shown in FIGS. 11A and 11B, fixing of the sliding element 22 to the holding member 21 is carried out such that the tongues 22d of the sliding element 22 are located above the bulged-out segment 21d of the holding member 21. When the base segment 22a of the sliding element 22 is pushed down, the tongues 22d are bent upwardly by the bulged-out segment 21d, and the ends of the tongues 22d ride over the bulged-out segment 21d, as shown in FIGS. 9 and 10. The extreme end portions of the tongues 22d remain bent upwardly and engage the lower part of the bulged-out segment 21d. As a result, the flat base segment 22a has been mounted on the flat surface 21b and the sliding element 22 is fixed to the holding member 21.
As described above, the holding member 21 having the sliding element 22 fixed thereto is rotatably attached to a shaft and the sliding piece 22b of the sliding element 22 can make sliding contact with a resistor or a contact point or the like. The sliding piece 22b is resiliently urged into contact with the resistor or the contact point or the like so as to perform an adjustment of a resistance value or a changing-over of contact point.
In addition, when the sliding element 22 is resiliently urged into contact with the resistor or the contact point or the like, as shown in FIG. 10, a force indicated by an arrow P1 is applied to the sliding piece 22b.
As illustrated in FIG. 10, the base segment 22a of the sliding element 22 exerts a force, in a direction of an arrow P2, applied by tongues 22d about a fulcrum point Y. The extremity ends of the tongues 22d are engaged with the column-like segment 21e, such that as the tongues 22d generate a push-back force. The base segment 22a is lifted up from the flat surface 21a at the base of the tongues 22d.
This lifting-up may generate not only an unstable contact to the sliding element 22 with the resistor or the contact point, but may also weaken the engagement state of the tongues 22d with the bulged-out segment 21d. This weakening is due to its repetition over a long period of time which results in a looseness in the fixing of the sliding element 22.
The prior art electrical component is constructed such that the holding member 21 is provided with the bulged-out segment 21d projected upwardly from the flat surface 21b and the tongues 22d of the sliding element 22 is engaged with the bulged-out segment 21d while being bent back upwardly. Thus, the prior art electrical component has a problem, in that when the base segment 22a of the tongues 22d is lifted up it causes an unstable contact of the sliding element 22.
Further, it may produce a problem that the engaged state of the tongues 22d with the bulged-out segment 21d is weakened due to a long term repetition of the lifted state and the fixed state of the sliding element 22 may become loose.
Further, a problem occurs in assembling the sliding element 22 and the holding member 21. In this assembly process, the tongues 22d must be located above the bulged-out segment 21d and, in this position, the sliding element 22 cannot rest on the flat surface 21b of the holding member 21. Thus, the sliding element 22 must be moveably supported during assembly. As a result, assembly of the prior art bracket is troublesome and expensive, and can result in an inferior product.